Longitudinal data on 120 Caucasian and African-American male and female children has been collected for up to 5 visits/years, spanning the prepubertal early pubertal ages. Data include body composition by dual-energy X-ray absorptiometry, fat distribution by computed tomography, energy expenditure by doubly-labeled water and indirect calorimetry, insulin sensitivity by intravenous glucose tolerance test and minimal model, lipid profile, hormone profile, dietary intake, physical activity, and physical fitness by maximal oxygen consumption. Body composition and fat distribution have been examined with respect to disease risk factors (lipids, insulin resistance); independent effects of ethnicity, adiposity, and visceral adiposity have been identified. In general, Caucasian children appear more at risk for cardiovascular disease and appear to be at greater risk for type 2 diabetes due to lower insulin sensitivity.